Photos show the reddish brown coins. “Phantom” coins or “phantom” currency are an unusual type of Japanese Yen coin made of ceramic during the metal shortages of WWII, according to an FAQ ...

Most of the buried coins were from Japan's medieval period, from the 13th to the 16th centuries. The Japanese did not start producing their own metal currency until the late 7th century.

The yen rose to an almost five-month high of 148.56 per dollar last week as a fall in U.S. Treasury yields and a rise in Japanese bond yields dented the attractiveness of the U.S. currency.

The U.S. dollar briefly fell below 150 yen for the first time this year early Thursday, as the Japanese currency is bolstered by expectations of more interest rate rises by the Bank of Japan and ...